Motor vehicle security system and security method

ABSTRACT

A motor vehicle security system for trucks, trailers and the like equipped with conventional fluid operated braking assemblies. The security system comprises a manually operable valve for controlling the application of fluid under pressure to the braking assemblies to manually set the vehicle brakes. The valve is arranged with a mechanical, key-operated lock for controlling and locking the valve in a selected position. When the valve is in a &#39;&#39;&#39;&#39;locked&#39;&#39;&#39;&#39; position it allows the brakes to be set and the vehicle maintained in situ to prevent the unauthorized movement thereof. The brake assemblies are also secured and locked to prevent the manual operation thereof by means of a conventional lockout tool.

ited States Patent Stevenson et al.

MOTOR VEHICLE SECURITY SYSTEM AND SECURITY METHOD Inventors: Billy E.Stevenson, Huntington Beach; Thomas R. Rumsey, Inglewood, both of Calif.

Royal Industries, Inc., Pasadena, Calif.

Filed: July 19, 1973 Appl. No.: 380,588

Related US. Application Data Division of Ser. No. 181,673, Sept. 20,1971, Pat. No. 3,770,324.

Assignee:

US. Cl 180/113, 180/114, 292/144 Int. Cl. B60k 27/00 Field of Search303/9, 89; 180/111, 112,

References Cited UNITED STATES PATENTS 8/1971 Silverman 292/1443,624,761 11/1971 Kohn 180/112 3,656,574 4/1972 Edwards 180/1143,735,834 5/1973 St. Onge 180/112 Primary Examiner-Allen N. KnowlesAttorney, Agent, or Firm-Christie, Parker & Hale [57] ABSTRACT A motorvehicle security system for trucks, trailers and the like equipped withconventional fluid oper-v ated braking assemblies. The security systemcomprises a manually operable valve for controlling the application offluid under pressure to the braking assemblies to manually set thevehicle brakes. The valve is arranged with a mechanical, key-operatedlock for controlling and locking the valve in a selected position. Whenthe valve is in a locked" position it allows the brakes to be set andthe vehicle maintained in situ to prevent the unauthorized movementthereof. The brake assemblies are also secured and locked to prevent themanual operation thereof by means of a conventional lockout tool.

8 Claims, 10 Drawing Figures PATENTED HAR 1 81975 SHEET 2 6 MOTORVEHICLE SECURITY SYSTEM AND SECURITY METHOD REFERENCE TO RELATEDAPPLICATIONS This application is a divisional application of mycopending application bearing Ser. No. 181,673, filed Sept. 20, 1971 andentitled MOTOR VEHICLE SECU- RITY SYSTEM AND SECURITY METHOD andassigned to the same assignee as the present application, now U.S. Pat.No. 3,770,324.

PRIOR ART AND SUMMARY OF THE INVENTION At the present time there is aneed for some mechanism to prevent the theft of motor vehicles. Thisneed is particularly apparent in commercial vehicles such as trucks,tractors, and trailers that are either individually or tandemlyoperated. These commercial vehicles, to a large extent, are providedwith service and emergency braking means that are normally fluidoperated. Some of these braking means are constructed in terms of lockthe vehicle wheels in the event of the loss of operating fluid, such asair under pressure at the brake assemblies. One such brake assembly isdisclosed in U.S. Pat. No. 3,285,672 granted on Nov. 15, 1966.

The present invention advantageously utilizes the air or fluid operatedbraking mechanisms that are normally provided with commercial vehiclessuch as trucks, trailers and tractors for the prevention of theft orimproper operation of the motor vehicle. The present inventioncomprehends a method for securing motor vehicles to prevent the theftthereof of the type of motor vehicle comprising a tractor and at leastone trailer coupled thereto having mechanically powered brake settingmeans operable from a fluid source for each of a plurality of wheels forsetting the brakes. The vehicle may be locked by manually setting thebrake operating means and then securing the set brake setting means. Inthis fashion a tractor, for example, may be decoupled from the trailerto leave the trailer in a locked and secured condition in situ therebypreventing its movement by unauthorized individuals.

The method specifically comprehends the operation of the brake settingmeans by coupling a manually operable control means for controlling theapplication of the fluid pressure to the braking means for setting thevehicle brakes. The method further includes signaling the locked orunlocked condition of the motor vehicle.

From an apparatus standpoint the present invention comprises a motorvehicle having a plurality of wheels and a source of pressurized air.The vehicle is provided with separate brake assemblies for each of theplurality of wheels and each are adapted to be activated to brakingposition by controlling the application of the pressurized air or fluidthereto. Pneumatic control means is coupled to the source of pressurizedair for activating the braking assembly. The braking assembly for themotor vehicle includes conventional, mechanically powered alternatebrake setting means coupled to the source of pressurized air to beoperated therefrom and to be maintained in a deactivated condition inresponse to the application of pressurized air thereto and automaticallyactivated to a brake setting position in response to the loss of thepressurized air. The system includes lockable valve means coupled inseries relationship with the source of pressurized air and themechanical brake setting means for controlling the application emergencyor booster spring brakes that automatically 2 of the pressurized airthereto and, thereby the set condition of the braking assembly. Thelockable valve means is adapted to be manually operable and locked in abrake setting position. The lock for the valve may be a conventionalmechanical key-operated lock adapted for operating the valve means.

These and other features of the present invention may be more fullyappreciated when considered in the light of the following specificationand drawings, in which:

FIG. 1 is a schematic illustration of the hydraulic system of a motorvehicle security system in an unlocked condition and embodying thepresent invention;

FIG. 2 is a schematic illustration of the motor vehicle security systemembodying the present invention and illustrating the hydraulic systemthereof in a locked condition;

FIG. 3 is a cross-sectional view of a conventional spring braking meansadapted for use in the hydraulic system of FIGS. 1 and 2 in accordancewith the present invention;

FIG. 4 is a perspective view of the lockable valve housing employed inthe hydraulic system of the present invention and illustrated in FIGS. 1and 2;

FIG. 5 is a left-hand end view of the valve detached from the valvehousing of FIG. 4, illustrating the lock condition signaling element;

FIG. 6 is a top plan view, with portions broken away, of the housingillustrated in FIG. 4;

FIG. 7 is a sectional view of the detached valve of FIG. 5 taken alongthe line 7-7 and illustrating in dotted outline its position within thehousing of FIG. 4;

FIG. 8 is an exploded view of the plug assembly employed for securingthe brake illustrated in FIG. 3;

FIG. 9 is a schematic illustration of the hydraulic system of a motorvehicle security system embodying the present invention and including anarrangement for locking the doors of a motor vehicle; and

FIG. 10 is a schematic illustration of another embodiment of the motorvehicle security system of the type illustrated in FIG. 9.

Now referring to the drawings, the motor vehicle security system will bedescribed as it may be employed with a conventional fluid operatedbraking means. One such conventional braking means that is particularlyadaptable for use with the present invention is the spring braking meanscommercially available from the Anchorlok Division of Royal Industries,Inc. of Compton, California. The structure of such a spring operatedbraking means and the hydraulic system conventionally employed therewithis described in U.S. Pat. No. 3,285,672 granted on Nov. 15, I966. Thespecific construction of a spring braking means adapted for use with thepresent invention is illustrated in FIG. 3. The spring braking meansadaptable for use with the present invention merely requires somemechanically powered brake actuating means that is operable in responseto the present or absence of fluid pressure applied thereto for settingthe conventional brakes of the motor vehicle. These braking systemsnormally are fluid operated and a conventional hydraulic circuit forsuch brakes is illustrated in FIG. 1 in combination with the lockablevalve means for embodying the security system of the present invention.

In FIGS. 1 and 2 there is illustrated a pair of wheels arranged onopposite sides of a motor vehicle such as may be found in a conventionaltruck or trailer. Each pair of wheels is provided with braking means Bcoupled to the source of fluid pressure illustrated as the tank T. Thefluid under pressure is supplied to the brakes B through suitable fluidconduits or piping P. The piping P is illustrated for bothservice/emergency and booster assemblies of the brakes B illustrated inFIG. 3. As illustrated in FIG. 1, lockable valve means L is arranged inserial relationship with an emergency conduit P coupled between the tankT and a T for coupling the tank S to each of the booster portions of thebrakes B. The lockable valve means L may be a three position valve forcontrolling the application of fluid under pressure or air to thebooster portions of the brakes B. As illustrated in FIG. 1 the valve Lis in an unlocked condition and therefore the fluid under pressure fromthe tank T is applied to the booster portions of the brakes B tomaintain them in a deactuated condition or the brakes OFF. When thevalve L is manually operated to tis braking operating position the linesP are depressurized as illustrated in FIG. 2. In this condition, thefluid under pressure is removed from the booster sections of the brakesB allowing the mechanically operated brakes to be applied. It will beseen from reviewing FIG. 2 that under these conditions the fluid underpressure from the tank T is blocked at the valve L thereby causing thebleeding or removal of the air at the boosters of the brakes B and theactuation of the brakes and preventing the movement of the vehicle.

Prior to examining the security system in more detail, at this point abrief description of the mechanical brake setting means B willfacilitate understanding of the invention. The conventional brakesetting means B as adapted for the present invention is illustrated inFIG. 3 in terms of a service/emergency brake actuating assembly having abooster assembly arranged in piggyback fashion therewith.

FIG. 3 illustrates in cross section a brake apparatus B that comprises aservice/emergency braking unit 11 connected with a booster unit 12 inthe conventional piggyback fashion. It will be appreciated by thoseskilled in the art that the brake apparatus B illustrated in FIG. 3 istypical of the brake apparatus applied to a pair of wheels of a truck ortractor, or tractor hauled trailer and that at least a pair of thewheels will carry the braking apparatus B. For this purpose, the brakingapparatus B is provided with a braking rod 13 for connection to theconventional brake shoe setting crank arm 13BS. It should be understoodthat the operation of the braking rod 13 effects the correspondingoperation of the brake shoe setting arm 13BS as is conventional in theprior art braking apparatus. The booster unit 12 of the brakingapparatus B is illustrated in FIG. 3 under the condition where the fluidunder pressure is fully applied to the booster unit 12 as it is arrangedin normal operation for parking purposes and emergency operation.

The construction of the booster unit 12 is of conventional constructionand such booster units are commercially available from the AnchorlokDivision of Royal Industries, Inc. of Compton, California. Briefly, thebooster unit 12 comprises a housing 138 including a booster diaphragm 14mounted across the housing to define a pair of chambers on oppositesides thereof. A chamber 15 is defined on the right side of the boosterdiaphragm 14, as illustrated in FIG. 3, defines a chamher for caging aconventional booster compression spring 16 therein. The compressionspring 16 is mounted against a floating bearing plate 17 mountedadjacent the right-hand side of the diaphragm l4 and the outer end ofthe housing 13B. In the illustrated caged or fully compressed conditionof the spring 16, the spring is maintained between the bearing plate 17and the adjacent wall 13a of the housing 138. It will be noted that thecompression spring 16 positions and holds the floating bearing plate 17against the face of the booster diaphragm 14. The opposite side of thebooster diaphragm l4 mounts a push rod 18 having push plates 20 and 21mounted to opposite ends thereof. The push rod 18 is maintained withinthe chamber 22 which may be considered as the fluid or air chamber forthe booster unit 12. The chamber 22 is dc.- fined by means of the fluidexposed surface of the diaphragm 14 further identified by the referencecharacter 14a, the opposite face of the chamber being defined by thehousing 138 proper and more particularly the wall identified by thereference numeral 13b. The push rod 18 is slidably mounted through thewall 13b of the housing in a fluid tight fashion to maintain the chamber22 properly pressurized. For this purpose an O ring 23 is mounted withinthe wall 13b. A spring 24 is mounted within the air chamber 22 betweenthe push rod plate 20 and the wall 13b of the housing 138 to maintain aminimum amount of pressure on the booster diaphragm 14 and thereby thecompression spring 16.

It should be recognized that with the fluid chamber 22 fully pressurizedthat the push rod 18 will be arranged as illustrated in FIG. 3. Upon thecomplete failure of the fluid pressure to the fluid chamber 22 or whenthe pressure within the chamber falls below a predetermined pressure thecompression spring 16 will be allowed to expand against the boosterdiaphragm 14 for moving the diaphragm to the left thereby operating thepush rod 18. The push rod 18, in turn, will be effective for operatingthe brake operating rod 13 through the service/emergency unit 11 andthereby the brake shoe setting arm 13BS sets the brake shoes in theusual fashion. The above-described booster unit 12 is of conventionalconstruction and the booster unit, per se, does not form a portion ofthe present invention.

The booster unit 12 is arranged in the conventional piggyback fashionwith the service/emergency unit 11 whereby the push rod plate 21 for thepush rod 18 is mounted within the service/emergency unit 11 proper toallow for the piggyback or tandem operation of the service/emergencyunit 11 and the booster unit 12.

To permit assembly and disassembly as well as servicing the boosterapparatus it is conventional to provide a lockout tool to place thespring 16 in a caged or compressed condition after it has been releasedto actuate the brakes. For the purpose of the present invention, then,it will be noted that an aperture is normally provided at the boosterexposed end of the housing 133 for receiving such a lockout tool andwhich aperture just be secured to prevent unauthorized operation of thebooster 12. The lockout tool may be carried on the side of the housingfor the Brake B in the manner disclosed in U.S. Pat. No. 3,291,004granted on Dec. 13, 1966. This aperture is illustrated in FIG. 3 as theaperture 30. To prevent the unauthorized operation of the booster 12,this opening is secured by a plug lock assembly 31 illustrated in FIG. 3in its secured position in the aperture 30. The same elements of pluglock assembly 31 are illustrated in an exploded form in FIG. 8. It isparticularly apparent from reviewing FIG. 8 that a conventional,mechanical lock core assembly 32 is employed with the plug lock body 33secured thereto by means of a lock pin 34. A plug lock seal 35 ismounted in abutting relationship with the plug lock body 33 at theshoulder 33A defined inwardly of the outer end thereof 5 and mountedaround the lock core assembly 32 forward of the opening 33C thatreceives the lock pin 34 and extends into the locking aperture 32a forthe core assembly 32. As is evident from FIG. 3, the outer end of theplug lock body 33 is provided with a flexible dust cover 36 that has adependent arm 36A mounting an apertured locking element 368 that issecured to the lock body 33 at the shoulder 33a between the shoulder andthe plug lock seal 35. The opposite end of the arm 36a carries thetriangular, flat cover 36C which is provided with a pair of locking tabs36: that secures to the corresponding locking apertures 33b provided forthe lock body 33 as best appreciated by examining FIG. 3.

The lock core assembly 32 is of conventional construction and is acommercially available key-operated lock. The assembly 32 receives a key32K of the type illustrated in FIG. 7, at the key receiving end of thecore assembly 32H. The operating end of the key 32K coacts with theapertures 32: and 32j arranged in the core assembly end 3211. With theplacement of the key 32 into the body 33 and assembly 32 the lock isrotatable between a locked and an unlocked position in a conventionalfashion. The right hand end of the lock core assembly 32 is threaded atthe section 32B and receives a plug lock cam 37 secured to the assembly32 by means of a nut 38. This assembly is held in place in the aperture30 and with the rotation of the key to the locked position, aperture 30is secured to prevent the unauthorized manual operation of the springbrake or booster assembly 12.

Now referring to FIGS. 4-7, the structure and operation of the rotatablevalve L will be described. The rotatable valve assembly L is providedwith a housing 40 which protects the valve from tampering and damage andalso houses the fittings for the conduits P so that they can bedisassembled only by unlocking with the key 32K. The pipes P are coupledbetween the source of pressurized fluid or tank T, the valve L and thebrakes B as described inconjunction with FIGS. 1 and 2. The housing 40may be mounted anywhere on the motor vehicle and when employed with atrailer the assembly may be mounted on the side or end of the trailerand secured to the trailer body by means of fasteners or the like. Forthis purpose the housing 40, as illustrated in FIG. 4, includes a pairof slots 408 having fastener securing openings 40 S-1 for receiving afastener for securing the housing 40 to the motor vehicle. The rotatablevalve L is mounted in the housing 40 with a lock of the same type asdescribed in conjunction with FIGS. 3 and 8 and mounted for manuallycontrolling the valve and locking it in the selected position. The bodyportion of the lock extends outwardly from the housing 40 to receive thekey 32K for operating the lock core assembly. The lock body isidentified by the reference numeral 40B and is arranged to extend fromthe outer face of the housing 40 with a pair of signaling apertures 40Land 40U arranged on opposite sides thereof. The aperture 40L is providedfor viewing the indicator signaling the locked condition of the brakeswhen the lock has been operated to this position, while the aperture 40Uallows the indicator to be viewed during the unlocked condition of thebrakes as illustrated in FIG. 4. The valve L housed within the housingincludes a signaling arm illustrated in dotted outline and identified bythe reference numeral 41 that is swingable between the two apertures 40Land 40U with the operation of the lock between the two positions so thatit either appears at the locked aperture 40L or the unlocked aperture40U for signaling the corresponding condition of the lock.

The valve L employed for the purposes of the present invention is a3-way valve which is arranged in serial relationship with the piping orconduits for conveying and blocking the fluid under pressure or air fromthe tanks T to the brakes B. In the blocked position the valve Lprovides a passage for conveying the fluid from the brakes B to theatmosphere to bleed" the booster assemblies. This valve may be anyconventional 3-way valve for effecting this function. The valve L isillustrated in section within the housing 40 in FIG. 7 along with thelock assembly. As illustrated in FIG. 7, the valve will be seen tocomprise a valve body 44 mounting a valve disc 45. The outer wall of thevalve disc 45 mounts a wave washer 46 secured thereto by means of aretaining ring 47. The retaining ring 47 is arranged with a washer 48and a second retaining ring 49. These latter mentioned elements surroundthe valve stem 50 which receives the conventional lock core assembly 51and is secured thereto by means of the set screw 52 secured to the valvestem 50 by means of a suitable aperture as illustrated. The lock corebody is secured to the inner wall of the housing 40 so as have its keyreceiving portion 40B extending from the outer wall of the housing 40 asdescribed hereinabove. The valve stem 50 also mounts the indicator 41 sothat it will be rotated in response to the operation of the lock andvalve stem 50 for setting of the valve L in its selected position andsignaling the position. The lock core assembly 51 is secured in positionby means of a fastener or nut 53 secured adjacent the inner wall of thehousing 40 as illustrated in FIG. 7.

It should also be noted that the housing 40 is constructed and definedwith a key holding receptacle 40K. The receptacle 40K is illustrated inthe lower right-hand portion of FIG. 7 and is utilized to store the key32K. The same key 32K is employed for operating all of the locks on anyone security system. This arrangement allows the plug lock assembly tobe unlocked and removed from the brakes B to allow the manual operationof the brakes and also to allow the interchangeability of the trailerswhen the system of the present invention is utilized withtractor-trailer combinations.

Now referring to FIG. 9, the hydraulic system for a motor vehicle forlocking the wheels of a motor vehicle as described hereinabove will bedescribed as the system may be modified to include means for locking thedoors of a motor vehicle. As illustrated in FIG. 9 the hydraulic systemis applied to the tractor of a tractortrailer combination for lockingthe doors of the trailer by means of the hydraulic system. It will beunderstood that the system may be applicable for locking the doors ofany motor vehicle whether it is the tractor, the trailer or thetractor-trailer combinatioon. In addition, the hydraulic system may beconstructed and defined to control the locking of the doors along withthe locking of the motor vehicle wheels simultaneously or independentlythrough separate hydraulic circuits.

The general arrangement of the hydraulic system i1- lustrated in FIG. 9is the same as that illustrated in conjunction with FIGS. 1 and 2. Thelockable valve means L of the previously disclosed embodiment isillustrated in the booster line to the brakes B. The lockable valve L isemployed to control the application of the pressurized air from the tankT to the brakes B as well as to the locking means 60 provided for thedoors 61 and 62 for the trailer schematically illustrated. The lockingmeans 60 is pneumatically operated and in this instance is mountedinside the trailer for the purpose of locking the trailer doors. Thelocking means 60 is characterized as being pneumatically operated tocontrol the application of a locking shaft 60L for locking and unlockingthe doors 61 and 62. It may be found convenient to utilize themechanically operated braking structures or the spring brakes B for thecontrollable locking means 60. The shaft 60L for the locking means 60 isadapted to be slidably received in looking ears 61L and 62L mounted onthe interior of the respective doors 61 and 62. It will be recognizedthat if the locking means 60 is a spring brake that it would require atremendous amount of force to pry the doors 61 and 62 loose when locked.

The locking means 60 is arranged in hydraulic circuit relationship withthe lockable valve L. For this purpose a T connection 63 is coupled intothe piping upstream of the T connection for coupling the tank T to eachof the booster portions of the brakes B. The T connection 63 is coupledto the locking means 60 through a circuit including a one-way checkvalve 64 and a T connection 65. One port of the T connection 65 isconnected to the check valve 64 while the other port is connected to thelocking means 60. The third port for the T connection 65 is connected toa manual pressure releasing valve 66 through a one-way check valve 67.The manual pressure release valve 66 may be adapted to be operated fromthe exterior of the motor vehicle or in this instance the trailer forcontrolling the application of the pressurized air to the locking means60. It will be recognized that the illustrated relationship of the checkvalves 64 and 67 is to block off the auxiliary piping for the lockingmeans 60-to the conventional piping system for operating the brakes B asdescribed hereinab'ove.

The system .of FIG. 9 is alsoadapted to allowthe motor vehicle operatorto control the application of both the brakes and the locking means 60through his normal driving position within the cab of the tractor. Forthis purpose, a conventional dash control valve 68 is provided. One portof the dash control valve 68 is connected to the piping identified asthe booster piping extending between the tank T and a port of the dashcontrol valve 68. The other port of the valve 68 is connected to oneport of the controllable lockable valve means L and, as in the previousembodiment, the outlet piping from the valve L is connected to the Tconnection 63.

From the above description, the operation of the hydraulic system forlocking the doors of a motor vehicle or a trailer should be evident. Thecontrol of the brakes Y B is the same as in the previous embodiment. Itwill also be recognized that with the provision of the control valve 68that it can be used to remove the pressurized air from the brakes Bthrough the operation thereof when the valve L is in an unlockedcondition. This operation will also set the locking means 60 in a lockedcondition. The locking of the valve L is effective for 8 setting thebrakes B and the locking means 60 in a locking condition at the sametime. In this embodiment the shaft 60L for the locking means 60 isoperative when the air under pressure is released from the chamber toallow the shaft 61L to lock the doors 61 and 62. The application ofpressurized air to the locking means 60 will withdraw the shaft 60L fromthe locking ears 6lL and 62L for unlocking the door. This may beeffected by operation of the lockable valve L to the unlocked positionor the manual pressure release valve 66. It will be understood that themanual pressure release valve is effective for applying the pressurizedair and bleeding out the pressurized air from the means 60. With thisarrangement, then, with the system applied to a trailer or atractor-trailer combination the wheels and the doors of the trailer maybe locked simultaneously. This may be accomplished while the tractor andthe trailer are coupled together and after the trailer is positioned inits desired location, the doors and the wheels may be locked in thisposition and location and the tractor decoupled from the trailer. I

Now referring to FIG. 10, another embodiment of the hydraulic system ofthe type discussed in combination with FIG. 9 will be described. In thisembodiment the trailer doors 61 and 62 are also adapted to be locked bymeans of a pneumatically operated means 60 in the same fashion asdescribed in the embodiment of FIG. 9. The hydraulic system in thisinstance has been simplified from that of FIG; 9 through the provisionof a single fluid conduit identified as the conduit PD that is coupledbetween the locking means 60 and a lockable valve L. In this instance,the lockable valveL' is substantially identical to that describedhereinabove except for an extra port provided on the valve L' forreceiving the one end of the conduit PD. In thisfashion, the lockablevalve L will be connected in an independent hydraulic circuit to thelocking means 60 from the conduit P coupled to the brakes B and both areopera-' ble through the valve L in the same general fashion as describedin combination with FIG. 9. Forthis purpose the dash control valve 68 isalso employed for controlling the application of the pressurized air tothe elementL ,andthe brakes B and element 60. The opera tion of thelockable valve element L', then, will control the locking and unlockingof the locking element60 with respect to the doors of the motor vehicleor the trailer. It should also be recognized that in accordance with theprevious description the positions of the lockable valve element L and Las embodied in the system of FIGS. 9 and 10 will also signal the lockedand unlocked condition of the doors and the brakes of the motor vehicle,tractor or trailer depending upon the application of the system of thepresent invention.

What is claimed is;

' 1. A motor vehicle security system comprising a vehicle having aplurality of wheels and at least one door, a source of pressurized air,controllable braking means coupled to the source of pressurized air,said braking means including mechanically powered alternate brakesetting means coupled to the source of pressurized air and maintained ina deactuated brake setting condition in response to the application ofpressurized'air thereto and effective to automatically set the brakingmeans upon failure of the pressurized air, said mechanically poweredbraking means including means for preventing the unauthorized operationof the braking means at said braking means,

controllable locking means arranged on the motor vehicle and connectedto control the locking and unlocking of at least the single door for themotor vehicle,

lockable valve means coupled to said source of pressurized air and beingmanually operable to a locked condition for setting the mechanicallypowered brake setting means and locking same in the set position,

said door locking means being coupled to the source of pressurized airthrough the lockable valve means to be placed in a locked and unlockedposition by the corresponding operation of the lockable valve means, and

control means accessible within the motor vehicle and coupled betweensaid source of pressurized air and the locking means for controlling theapplication of the source of pressurized air to said locking means.

2. A motor vehicle security system as defined in claim 1 wherein thecontrollable door locking means is mechanically powered lock settingmeans.

3. A motor vehicle security system as defined in claim 2 wherein thelock setting means is in the form of spring braking means.

4. A motor vehicle security system as defined in claim 1 wherein thecontrol means is coupled between the source of pressurized air, thebraking means and the locking means to control the application of thepressurized air to the braking means and locking means substantiallysimultaneously.

5. A motor vehicle security system as defined in claim 1 includingunlocking means coupled to said locking means and mounted to beaccessible outside to the motor vehicle for controlling the applicationof pressurized air to the locking means to thereby unlock the motorvehicle door.

6. A motor vehicle security system as defined in claim 1 includingmanually controlled valve means connected to said source of pressurizedair to receive the pressurized air readily accessible to the vehicleoperator from his normal driving position to control the venting ofpressurized air from said locking means.

7. A motor vehicle security system as defined in claim 1 wherein themotor vehicle is a tractor-trailer combination and the locking means islocated inside the trailer for locking at least one trailer door.

8. A method for securing motor vehicles to prevent the theft thereof,the motor vehicle being of the type having a tractor and at least onetrailer coupled thereto, including the steps of providing at least thetrailer of a tractor-trailer combination with mechanically powered brakesetting means,

manually operating the mechanically powered brake setting means to setthe brakes on at least the trailer,

securing the set brake setting means at the brake to preventunauthorized resetting of the brake setting means, providing at leastthe door of the trailer of the tractor-trailer with a pneumaticallyoperated lock,

decoupling the tractor from the trailer to leave the trailer in situ inthe locked and secured condition, and

setting the lock for the trailer door before decoupling the tractor fromthe trailer.

=l l l= =l

1. A motor vehicle security system comprising a vehicle having aplurality of wheels and at least one door, a source of pressurized air,controllable braking means coupled to the source of pressurized air,said braking means including mechanically powered alternate brakesetting means coupled to the source of pressurized air and maintained ina deactuated brake setting condition in response to the application ofpressurized air thereto and effective to automatically set the brakingmeans upon failure of the pressurized air, said mechanically poweredbraking means including means for preventing the unauthorized operationof the braking means at said braking means, controllable locking meansarranged on the motor vehicle and connected to control the locking andunlocking of at least the single door for the motor vehicle, lockablevalve means coupled to said source of pressurized air and being manuallyoperable to a locked condition for setting the mechanically poweredbrake setting means and locking same in the set position, said doorlocking means being coupled to the source of pressurized air through thelockable valve means to be placed in a locked and unlocked position bythe corresponding operation of the lockable valve means, and controlmeans accessible within the motor vehicle and coupled between saidsource of pressurized air and the locking means for controlling theapplication of the source of pressurized air to said locking means.
 2. Amotor vehicle security system as defined in claim 1 wherein thecontrollable door locking means is mechanically powered lock settingmeans.
 3. A motor vehicle security system as defined in claim 2 whereinthe lock setting means is in the form of spring braking means.
 4. Amotor vehicle security system as defined in claim 1 wherein the controlmeans is coupled between the source of pressurized air, the brakingmeans and the locking means to control the application of thepressurized air to the braking means and locking means substantiallysimultaneously.
 5. A motor vehicle security system as defined in claim 1including unlocking means coupled to said locking means and mounted tobe accessible outside to the motor vehicle for controlling theapplication of pressurized air to the locking means to thereby unlockthe motor vehicle door.
 6. A motor vehicle security system as defined inclaim 1 including manually controlled valve means connected to saidsource of pressurized air to receive the pressurized air readilyaccessible to the vehicle operator from his normal driving position tocontrol the venting of pressurized air from said locking means.
 7. Amotor vehicle security system as defined in claim 1 wherein the motorvehicle is a tractor-trailer combination and the lockIng means islocated inside the trailer for locking at least one trailer door.
 8. Amethod for securing motor vehicles to prevent the theft thereof, themotor vehicle being of the type having a tractor and at least onetrailer coupled thereto, including the steps of providing at least thetrailer of a tractor-trailer combination with mechanically powered brakesetting means, manually operating the mechanically powered brake settingmeans to set the brakes on at least the trailer, securing the set brakesetting means at the brake to prevent unauthorized resetting of thebrake setting means, providing at least the door of the trailer of thetractortrailer with a pneumatically operated lock, decoupling thetractor from the trailer to leave the trailer in situ in the locked andsecured condition, and setting the lock for the trailer door beforedecoupling the tractor from the trailer.